From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: linux-next: Tree for August 27 Date: Sat, 30 Aug 2008 11:10:25 +0200 Message-ID: <48B90E81.5060905@kernel.org> References: <20080827183453.eb651f50.sfr@canb.auug.org.au> <48B7C361.9070008@kernel.org> <20080829094249.GQ20055@kernel.dk> <200808292123.07246.bzolnier@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from hera.kernel.org ([140.211.167.34]:55465 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751025AbYH3JM0 (ORCPT ); Sat, 30 Aug 2008 05:12:26 -0400 In-Reply-To: <200808292123.07246.bzolnier@gmail.com> Sender: linux-next-owner@vger.kernel.org List-ID: To: Bartlomiej Zolnierkiewicz Cc: Jens Axboe , Stephen Rothwell , linux-next@vger.kernel.org, LKML , Ingo Molnar , dm-devel@redhat.com Hello, Bartlomiej Zolnierkiewicz wrote: >>> Hmmm... it broke booting? Bart, can you please elaborate a bit what got >>> broken? Did it fail to locate the root partition or were you using >>> static device nodes? >> It works fine for me, fwiw. > > It fails to locate the root partition if you are using the default root > device on x86 (the one hard-wired into bzImage, it uses hard-coded 8-bit > major/minor numbers). Right. That would break it too. > Now I see that the issue is easily fixed by passing the root device name > with "root=" (since it will figure out the actual major/minor numbers > later) and that the default root device is said to be deprecated according > to Documentation/x86/boot.txt (OTOH there is no warning at all that it is > deprecated and that you should be using "root=" so I'm not convinced that > I'm the only one who would hit the unfortunate combination). Yeap, in retrospect, enabling BLOCK_EXT_DEVT by default seems too disruptive. There also are people running off static /dev. I hope distros enable it during their alphas and betas tho so that they can spot problems in configuration utilities and stuff early. > Actually it seems that CONFIG_DEBUG_BLOCK_EXT_DEVT introduction (which I > think is a nice step forward) is a good oportunity to put the deprecation > of the default root device further, i.e. it may be worth to hook the > default root device check and/or CONFIG_DEBUG_BLOCK_EXT_DEVT one into > mount_block_root(). Maybe we can add a warning there if BLOCK_EXT_DEVT is enabled or do you have something else on mind? Thanks. -- tejun